openmedialibrary/oml/localnodes.py

# -*- coding: utf-8 -*-
# vi:si:et:sw=4:sts=4:ts=4

import socket

import netifaces
from zeroconf import (
    ServiceBrowser, ServiceInfo, ServiceStateChange, Zeroconf
)
from tornado.ioloop import PeriodicCallback

import settings
import state
from tor_request import get_opener

import logging
logger = logging.getLogger(__name__)


def can_connect(data):
    try:
        opener = get_opener(data['id'])
        headers = {
            'User-Agent': settings.USER_AGENT,
            'X-Node-Protocol': settings.NODE_PROTOCOL,
            'Accept-Encoding': 'gzip',
        }
        if ':' in data['host']:
            url = 'https://[{host}]:{port}'.format(**data)
        else:
            url = 'https://{host}:{port}'.format(**data)
        opener.addheaders = list(zip(headers.keys(), headers.values()))
        opener.timeout = 1
        r = opener.open(url)
        version = r.headers.get('X-Node-Protocol', None)
        if version != settings.NODE_PROTOCOL:
            logger.debug('version does not match local: %s remote %s (%s)', settings.NODE_PROTOCOL, version, data['id'])
            return False
        c = r.read()
        return True
    except:
        pass
        #logger.debug('failed to connect to local node %s', data, exc_info=True)
    return False

def get_broadcast_interfaces():
    return list(set(
        addr['addr']
        for iface in netifaces.interfaces()
        for addr in netifaces.ifaddresses(iface).get(socket.AF_INET, [])
        if addr.get('netmask') != '255.255.255.255' and addr.get('broadcast')
    ))

class LocalNodes(dict):
    service_type = '_oml._tcp.local.'
    local_info = None
    local_ips = None

    def __init__(self):
        if not settings.server.get('localnode_discovery'):
            return
        self.setup()
        self._ip_changed = PeriodicCallback(self._update_if_ip_changed, 60000)

    def setup(self):
        self.local_ips = get_broadcast_interfaces()
        self.zeroconf = {ip: Zeroconf(interfaces=[ip]) for ip in self.local_ips}
        self.register_service()
        self.browse()

    def _update_if_ip_changed(self):
        local_ips = get_broadcast_interfaces()
        if local_ips != self.local_ips:
            self.close()
            self.setup()

    def browse(self):
        self.browser = {
            ip: ServiceBrowser(self.zeroconf[ip], self.service_type, handlers=[self.on_service_state_change])
            for ip in self.zeroconf
        }

    def register_service(self):
        if self.local_info:
            for local_ip, local_info in self.local_info:
                self.zeroconf[local_ip].unregister_service(local_info)
            self.local_info = None

        local_name = socket.gethostname().partition('.')[0] + '.local.'
        port = settings.server['node_port']
        desc = {
            'username': settings.preferences.get('username', 'anonymous')
        }
        self.local_info = []
        for i, local_ip in enumerate(get_broadcast_interfaces()):
            if i:
                name = '%s-%s [%s].%s' % (desc['username'], i, settings.USER_ID, self.service_type)
            else:
                name = '%s [%s].%s' % (desc['username'], settings.USER_ID, self.service_type)
            local_info = ServiceInfo(self.service_type, name,
                                     socket.inet_aton(local_ip), port, 0, 0, desc, local_name)
            self.zeroconf[local_ip].register_service(local_info)
            self.local_info.append((local_ip, local_info))

    def __del__(self):
        self.close()

    def close(self):
        if self.local_info:
            for local_ip, local_info in self.local_info:
                try:
                    self.zeroconf[local_ip].unregister_service(local_info)
                except:
                    logger.debug('exception closing zeroconf', exc_info=True)
            self.local_info = None
        if self.zeroconf:
            for local_ip in self.zeroconf:
                try:
                    self.zeroconf[local_ip].close()
                except:
                    logger.debug('exception closing zeroconf', exc_info=True)
            self.zeroconf = None
        for id in list(self):
            self.pop(id, None)

    def on_service_state_change(self, zeroconf, service_type, name, state_change):
        if not '[' in name:
            id = name.split('.')[0]
        else:
            id = name.split('[')[1].split(']')[0]
        if id == settings.USER_ID:
            return
        if state_change is ServiceStateChange.Added:
            info = zeroconf.get_service_info(service_type, name)
            if info:
                self[id] = {
                    'id': id,
                    'host': socket.inet_ntoa(info.address),
                    'port': info.port
                }
                if info.properties:
                    for key, value in info.properties.items():
                        key = key.decode()
                        self[id][key] = value.decode()
                logger.debug('add: %s', self[id])
                if state.tasks:
                    state.tasks.queue('addlocalinfo', self[id])
        elif state_change is ServiceStateChange.Removed:
            logger.debug('remove: %s', id)
            self.pop(id, None)
            if state.tasks:
                state.tasks.queue('removelocalinfo', id)

    def get(self, user_id):
        if user_id in self and can_connect(self[user_id]):
            return self[user_id]